Spark-plug.



C. K. AUSTIN.

SPARK PLUG APPLICATION LED JAN. 16, !9 4 Paemed Dec. 28, 1915 je %77 JJMJ a 7 M W b W J J, a z

CASSINUSS KENDALL AUSTIN, OF WOODSTOCK, ILLINOIS.

SPARK-PLUG.

Specification o! Letters Patent.

Pateted Dec. 28, 1915.

Application filed January 16, 1914. Serial No. 812399.

To all whom it may concem Be it known that I, CASSINUSS KENDALL AUSTIN, a citizen of the United States, and a resident of Woodstock, in the county of McHenry and State of Illinois, have invented certain new and useful Improvements in Spark-Plugs; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to spark plugs adapted to be used for ignition purposes in connection with internal combustion engines.

The princip-al object of the invention is to provide a simple, economical and efiicient sparkplug for internal combustion engines.

A further object of the invention is to provide a spark plug comprising a plurality of conducting wires or electrodes surrounded by insulating material and adapted to enable oneor more of the electrodes surrounded by insulating material to be grounded or held incontact with a metallic part at a point or points protected or covered by the nsulator, so as to prevent to as great an extent as possible the accumulation of products of combustion or other unde sirable substances tending to foul the plug or produce a short circuit.

A further object of the invention is to provide an insulator having a plurality of electrodes therein, all adapted to be removably mounted in a metallic part and'to be readily removed and cleaned, or repaired,

and replaced in an efficient manner.

Other and further objectsof the invention will appear from the accompanying description and claim and from an inspection of the accompanying drawings.

The invention consists in the features, combinations of elements, and details of construction herein described and claimed.

In the accompanying drawings, Figure 1 is a View in central sectional elevation of a spark plug constructed in accordance with my invention and improvements; and Fig. 2, a similar View in central sectional elevation of another form of spark plug con structe'd in accordance with my invention.

In constructing a spark plug in accordance with my invention and improvements n the form shown in Fig. 1 of the drawings, I provide a core a of porcelain, mica, or similar non-conducting material. The core s, by preference, provided with an annular enlargement or shouldered portion b having, by preference, upwardly and inwardly tapered surface portions adapted to engage a similar opening 0 in a metallic bushing, sleeve or nut d which encircles the core and is provided with a shouldered portion e adapted to enable the bushing or nut to bescrewed into and out of operative position. The bushing or nut d has suitable outer screw-threads f which are adapted toengage similar inner screw-threads g in a metallic supporting member, such as the outer or main metallic body portion h of the plug. The main body portion h of the plug has outer screw-threads h' adapted to enable the plug to be Secured to an ignition chamber or an engine cylinder or cylinder head, and is provided with a central aXial opening z' therethrough, said axial opening having, by preference, a portion k of relatively large diameter adapted to admit the shouldered portion I) of the core, the sleeve or bushing d, and a gasket Z. Said gasketis formed of suitable compressible material adapted to encircle the core and form a tight joint between the insulating core and the main body of the plug h, and is interposed between the core and the shouldered main body portion of the plug.

An aperture m extends longitudinally through or from end to end of the core, and inthis aperture is mounted a wire or electrode n, formed of metal or other suitable electrically conductive material, one end o of which is adapted to be connected with a wire or other suitable member 3 of an electric circuit, and the opposite end ;o of which forms a sparking point which is located adjacent to a similar sparking point (1 for-med by a corresponding end portion of a metallic wre or electrode ?u The wire or electrode 7- is mounted in position to cxtcnd through a longitudinal opening s in the same core or insulator a in which the clectrode n is mounted. The elcctrodes are thus insulated 4 'or electrical connection between the wire r i and sad surrounding metallic member. The.

end u and point of contact between the wire %or ground wire and metallic bushing d are thus covered and protected by the insulating material 'and inclosed within the metallic sleeve or bushing d, so that no foul matter or foreign substance can reach the point of. contact. I V v The wire n is, by preference, provided with a screw-threa ed part or connecting member 0, having a nut 'v in threaded engagement therewith and adapted to be held in position upon the outer end'of the insulating core. A threaded' thumb nut or connecting member w is mounted in threaded engagement with the wire n and is adapted to securely connect a metallic wire or other suitable member of an electric circuit with the wire n, so that the latter is embraced within an electric circuit of which the mem- -bers 'J and 7' each form a' part, and which circuit may be of any desired'or known form, comprising, or connected with a suitable source of electric supply.

In making a spark plug of the form shown in Eig. 2, a core 2 of insulatingma-terial, suchas porcelain or mica, is provided having an enlarged or annularly shouldered end portion 3. A metallic threaded encircling sleeve or bushing 4: is shrunk or sweated upon the core, and is, by preference, provided with a suitable shouldered or nut portion 5 adapted to enable the sleeve to be screwed into threaded engagement with a relatively large inner threaded portion 6 of a central aperture 7 in the main metallic body portion 8 of the spark plug', so as to hold the core and the electrodes in operative position. The main metallic body 8 of the plug is provided with outer screw threads 9' adapted to enable the plug to be mounted in threaded engagement with an ignition chamber, or the cylinder or cylinder head of an engine or other device in connection with which the plug is to be used. A gasket 10 of suitable compressible material is interposed between the end of the body portion 8 of the plug and the sleeve 4, preferably at a point located between the member 8 and the shoulder 3 of the core 2. A metallic wire or electrc conductor 11 extendsthrough a suitable longitudinal or axial opening 12 in the core 2 of insulating material and s provided at its outer projecting threaded end,

adjacent to the end portion or sparking point 19 of the wire 11, already described, are mounted in suitable openngs in the core 2 of insulating material in such position that 'the end 20 of each of said wires 17 extends a suitable electrical conductor within the electric circuit which thus includes the insulated wires or electrodes 11 and 17 and the metallic members 4 and 8 of the plug.

From the foregoing it willbe seen that a core of insulated material having a lurality of electrodes therein, as describe is adapted to be readily removed and replaced and with it the electrodes, so that the core and electrodes can be examined and cleaned or repaired with facility. The points of contact between the electrodes which have their grounded or contact ends encircled by and in contact with a metallic plug member, are

removably held in position to maintain such` contact, or to form an electrical connection between such electrodes and the adjacent surface of such metallic member, by means of the threaded connection between the coreencircling sleeve and the corresponding plug member with which the sleeve is removably connected.

I claim:

A spark plug, comprising a core or wire holder made of non-conductive material, at least three wires therein, and terminating in adjacent points at one end of said holder, one of said wires being longer than the other wires, and said longer wire extending substantially the full length of the holder and adapted to be connected with an electric circuit, the shorter wires extending to points intermediate the ends of said holder and there being exposed, a metallic sleeve surrounding said holder and adapted to be secured to the wall of an explosion chamber, and :n :nulur metnllic member inserted in and held within said sleeve, said annular ncmbm' living in contact with the exposed cnds of said shorter wires.

In Lestimony that 1 claim the foregoing as my im'enton l alix my signature in the CASSINUSS KENDALL AUSTIN.

witnesses:

A. ERNEST SCHROEDER, HAROLD W. FRAME.

copies o: thi patent my be obtained !or five cents each, by addressng the "Commiioner o! Patents, Washington, D. c." 

